Why is there no effective vaccine against the flu?

Answer 1

Vaccines take months to make, so people have to guess which strains of flu are going to be active long in advance.

Answer 2

Because flu viruses rapidly change and mutate. Sometimes they change faster than the virus can be turned into a vaccine. It takes time to produce the virus (grow it in eggs usually) that is needed to make the vaccine. Sometimes a specific virus is difficult to culture (grow) and before enough can be produced, the virus has mutated to a new form.

There are short cuts to make enough vaccine from slow growing viruses by using adjuvants which are chemicals that increase the immune response so that less vaccine is needed to cause immunity. There is controversy over the use of adjuvants, and the vaccines for flu in the US do not usually contain adjuvants.

Answer 3

There are safe and effective vaccines against many different types of flu. Each vaccine is effective against only one particular type of flu, however. And flu viruses can mutate into new forms that are not prevented by the old vaccine, that is why new vaccines are made each flu season for the new mutations. But once you have been vaccinated for a particular type of flu virus, and if you are otherwise healthy, you will have effective lifetime immunity to that particular flu if it ever comes back around again as flu viruses often do.

The cold viruses are similar, although they mutate so rapidly that it is not usually possible to grow the virus and create a vaccine quickly enough for a new cold virus before it has mutated again to new forms for which the prior vaccines are not effective.

Answer 4

There now is a vaccine for the Swine Flu and it has proven effective in preventing the swine flu. Initially there was not a vaccine because the A-H1N1/09 flu virus was brand new. It had not been identified/seen before and so no specific vaccine had been developed for it before the need arose with the introduction of the new virus found in Mexico in early 2009. They were able to quickly produce a vaccine just in time for the 2009 flu season. See related question below for more background and history of the vaccine.

Answer 5

It is now. Since the 2010-2011 flu season, the seasonal flu vaccine has contained the swine flu vaccine in addition to two other types of flu vaccines that were selected for each specific flu season. There is no longer a need to get two flu vaccinations like was required in the 2009-2010 flu season during the pandemic.

Answer 6

Viruses mutate very quickly. This means that by the time you figure out a vaccine, there's usually another form of the virus already going around. This is why we can't find a vaccine for the ordinary cold!

With the flu virus, there are only a few varieties, but the scientists have to try to figure out which ones are most likely to be going around during the next flu season and make that kind. They can't make a vaccine with every single flu virus in it, because it would take too long to make and nobody could afford to buy it.

Answer 7

You can be (most people can) and you should be, especially if you are in the high risk groups for catching and having complications from the virus infection. See the related questions below.